Run pub tests against older versions of barback.

third_party/pkg/barback-0.13.0/lib/src/serialize.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library barback.serialize;
 
 import 'dart:async';
 import 'dart:isolate';
 
 import 'package:stack_trace/stack_trace.dart';
 
-import 'asset/asset_id.dart';
+import 'asset_id.dart';
 import 'utils.dart';
 
 /// Converts [id] into a serializable map.
 Map serializeId(AssetId id) => {'package': id.package, 'path': id.path};
 
 /// Converts [stream] into a [SendPort] with which another isolate can request
 /// the data from [stream].
 SendPort serializeStream(Stream stream) {
   var receivePort = new ReceivePort();
   receivePort.first.then((sendPort) {
@@ skipping 15 matching lines @@
 
 /// Convert a [SendPort] whose opposite is waiting to send us a stream into a
 /// [Stream].
 ///
 /// No stream data will actually be sent across the isolate boundary until
 /// someone subscribes to the returned stream.
 Stream deserializeStream(SendPort sendPort) {
   return callbackStream(() {
     var receivePort = new ReceivePort();
     sendPort.send(receivePort.sendPort);
+    // TODO(nweiz): use a const constructor for StreamTransformer when issue
+    // 14971 is fixed.
     return receivePort.transform(
-        const StreamTransformer(_deserializeTransformer));
+        new StreamTransformer(_deserializeTransformer));
   });
 }
 
 /// The body of a [StreamTransformer] that deserializes the values in a stream
 /// sent by [serializeStream].
 StreamSubscription _deserializeTransformer(Stream input, bool cancelOnError) {
   var subscription;
   var transformed = input.transform(new StreamTransformer.fromHandlers(
       handleData: (data, sink) {
     if (data['type'] == 'data') {
@@ skipping 55 matching lines @@
 /// A regular expression to match the exception prefix that some exceptions'
 /// [Object.toString] values contain.
 final _exceptionPrefix = new RegExp(r'^([A-Z][a-zA-Z]*)?(Exception|Error): ');
 
 /// Get a string description of an exception.
 ///
 /// Many exceptions include the exception class name at the beginning of their
 /// [toString], so we remove that if it exists.
 String _getErrorMessage(error) =>
   error.toString().replaceFirst(_exceptionPrefix, '');